Epidermolysis bullosa simplex with muscular dystrophy associated with PLEC deletion mutation.
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ABSTRACT:
SUBMITTER: Alvarez VC
PROVIDER: S-EPMC5061415 | biostudies-literature | 2016 Dec
REPOSITORIES: biostudies-literature
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Epidermolysis bullosa simplex with muscular dystrophy associated with <i>PLEC</i> deletion mutation.
Alvarez Valeria Carolina VC Penttilä Sini Tellervo ST Salutto Valeria Luján VL Udd Bjarne B Mazia Claudio Gabriel CG
Neurology. Genetics 20161011 6
Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disorder characterized by neonatal blistering and later-onset muscle weakness. ...[more]
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Project description:BACKGROUND:Epidermolysis bullosa simplex with muscular dystrophy (EBS-MD; OMIM #226670) is an autosomal recessive disease, characterized mainly by skin blistering at birth or shortly thereafter, progressive muscle weakness, and rarely by alopecia. EBS-MD is caused by mutations in the PLEC gene (OMIM *601282), which encodes plectin, a structural protein expressed in several tissues, including epithelia and muscle. We describe a patient affected with EBS-MD and diffuse alopecia in which we identified a novel pathogenic mutation by PCR amplification of all coding exons and exon-intron boundaries of PLEC gene, followed by bidirectional Sanger sequencing. CASE PRESENTATION:The patient, a 28-year-old female and only child of consanguineous healthy parents, was born after uneventful pregnancy. At 2 days of age, she developed skin and oral mucosal blistering, accompanied by voice hoarseness. On physical examination as an adult, we observed diffuse non-scarring alopecia on the scalp, onychodystrophy (pachyonychia) in all 20 nails, dental decay, mild dysphonia, and severe muscle atrophy mainly affecting the extremities. Neurological examination showed profoundly diminished reflexes. Mutation analysis revealed the patient to be homozygous for the novel PLEC nonsense mutation - c.7159G?>?T (p.Glu2387*) - located in exon 31. Thismutation predicts the lack of expression of the full-length plectin isoform. CONCLUSION:The present case appears to be the second association of EBS-MD with diffuse alopecia, both cases having different mutations involving PLEC exon 31. It remains to be elucidated whether diffuse alopecia results from PLEC mutations and/or from environmental factors.
| S-EPMC5775598 | biostudies-literature
Project description:Mutations of the human plectin gene (PLEC) on chromosome 8q24 cause autosomal recessive epidermolysis bullosa simplex with muscular dystrophy (EBS-MD). In the present study we analyzed the downstream effects of PLEC mutations on plectin protein expression and localization, the structure of the extrasarcomeric desmin cytoskeleton, protein aggregate formation and mitochondrial distribution in skeletal muscle tissue from three EBS-MD patients. PLEC gene analysis in a not previously reported 35-year-old EBS-MD patient with additional disease features of cardiomyopathy and malignant arrhythmias revealed novel compound heterozygous (p.(Phe755del) and p.(Lys1040Argfs*139)) mutations resulting in complete abolition of plectin protein expression. In contrast, the other two patients with different homozygous PLEC mutations showed preserved plectin protein expression with one only expressing rodless plectin variants, and the other markedly reduced protein levels. Analysis of skeletal muscle tissue from all three patients revealed severe disruption of the extrasarcomeric intermediate filament cytoskeleton, protein aggregates positive for desmin, syncoilin, and synemin, degenerative myofibrillar changes, and mitochondrial abnormalities comprising respiratory chain dysfunction and an altered organelle distribution and amount.Our study demonstrates that EBS-MD causing PLEC mutations universally result in a desmin protein aggregate myopathy phenotype despite marked differences in individual plectin protein expression patterns. Since plectin is the key cytolinker protein that regulates the structural and functional organization of desmin filaments, the defective anchorage and spacing of assembled desmin filaments is the key pathogenetic event that triggers the formation of desmin protein aggregates as well as secondary mitochondrial pathology.
| S-EPMC4847350 | biostudies-literature
Project description:Epidermolysis bullosa simplex with muscular dystrophy (MD-EBS) is a disease characterized by generalized blistering of the skin associated with muscular involvement. We report that the skin of three MD-EBS patients is not reactive with antibodies 6C6, 10F6, or 5B3 raised against the intermediate filament-associated protein plectin. Immunofluorescence and Western analysis of explanted MD-EBS keratinocytes confirmed a deficient expression of plectin, which, in involved skin, correlated with an impaired interaction of the keratin cytoskeleton with the hemidesmosomes. Consistent with lack of reactivity of MD-EBS skin to plectin antibodies, plectin was not detected in skeletal muscles of these patients. Impaired expression of plectin in muscle correlated with an altered labeling pattern of the muscle intermediate filament protein desmin. A deficient immunoreactivity was also observed with the monoclonal antibody HD121 raised against the hemidesmosomal protein HD1. Furthermore, immunofluorescence analysis showed that HD1 is expressed in Z-lines in normal skeletal muscle; whereas this expression is deficient in patient muscle. Colocalization of HD1 and plectin in normal skin and muscle, together with their impaired expression in MD-EBS tissues, strongly suggests that plectin and HD1 are closely related proteins. Our results therefore provide strong evidence that, in MD-EBS patients, the defective expression of plectin results in an aberrant anchorage of cytoskeletal structures in keratinocytes and muscular fibers leading to cell fragility.
| S-EPMC507309 | biostudies-other
Project description:Plectin is a widely expressed cytomatrix component involved in the attachment of the cytoskeleton to the plasma membrane. We have recently reported that the skin and muscles of three patients affected by epidermolysis bullosa simplex with muscular dystrophy (MD-EBS), a genetic disorder characterized by skin blistering associated with muscle involvement, are not reactive with antibodies specific to plectin. We demonstrated that in the skin, lack of plectin leads to failure of keratin filaments to connect to the plasma membrane via the hemidesmosomes, whereas in the muscle the deficient expression of the molecule correlates with an aberrant localization of desmin in the muscle fibers. In this study we demonstrate that in a MD-EBS kindred with two affected members, the disease results from a homozygous nonsense mutation in the plectin (PLEC1) gene leading to a premature stop codon (CGA to TGA) and decay of the aberrant plectin messenger RNA. The segregation of the mutated allele implicates the mutation in the pathology of the disorder. These results confirm the critical role of plectin in providing cell resistance to mechanical stresses both in the skin and the muscle.
| S-EPMC507667 | biostudies-other
Project description:Plectin is a cytoskeletal linker protein which has a long central rod and N- and C-terminal globular domains. Mutations in the gene encoding plectin (PLEC) cause two distinct autosomal recessive subtypes of epidermolysis bullosa: EB simplex (EBS) with muscular dystrophy (EBS-MD), and EBS with pyloric atresia (EBS-PA). Previous studies have demonstrated that loss of full-length plectin with residual expression of the rodless isoform leads to EBS-MD, whereas complete loss or marked attenuation of expression of full-length and rodless plectin underlies the more severe EBS-PA phenotype. However, muscular dystrophy has never been identified in EBS-PA, not even in the severe form of the disease. Here, we report the first case of EBS associated with both pyloric atresia and muscular dystrophy. Both of the premature termination codon-causing mutations of the proband are located within exon 32, the last exon of PLEC. Immunofluorescence and immunoblot analysis of skin samples and cultured fibroblasts from the proband revealed truncated plectin protein expression in low amounts. This study demonstrates that plectin deficiency can indeed lead to both muscular dystrophy and pyloric atresia in an individual EBS patient.
| S-EPMC3023027 | biostudies-literature
Project description:BackgroundPlectin, a large linker protein found in many tissues, acts to connect components of the cytoskeleton to each other. In the epidermis, plectin binds keratin intermediate filaments to hemidesmosomes. A deficiency of plectin in the skin leads to blister formation in the basal layer and the disease epidermolysis bullosa simplex (EBS).Hypothesis/objectivesTo describe a novel blistering disease that arose spontaneously in a litter of puppies.AnimalsTwo female and one male 20-day-old Eurasier puppies, from a litter of six, were presented for evaluation of failure to thrive and then euthanized due to poor prognosis. The puppies had ulcers on the lips, tongue, nasal planum, paw pads and abdomen.ResultsImmunolabelling on frozen skin for basement membrane proteins revealed patchy and weak to absent staining for plectin as compared with strong linear staining in normal dogs. Ultrastructurally, hemidesmosomes were irregularly shaped and had loss of distinction between inner and outer plaques. Pedigree analysis supported an autosomal recessive mode of inheritance. A premature stop codon was discovered in exon 27 of PLEC that resulted in the production of a severely truncated protein.ConclusionThe study describes the first documented spontaneous EBS associated with a PLEC variant in domestic animals.
| S-EPMC5324056 | biostudies-literature
Project description:The aim of the present study was to identify the causative gene defects associated with epidermolysis bullosa simplex (EBS) in a pedigree. The diagnosis of EBS was confirmed in two patients from that pedigree based on the clinical manifestations, histopathological examination of the skin and family history. Blood samples were collected from 6 family members and 100 heathy controls, and genomic DNA and RNA were extracted. Mutation analysis of the keratin 5 gene (KRT5) was conducted using polymerase chain reaction (PCR) direct sequencing and PCR-restriction fragment length polymorphism. In the pedigree, the results of PCR direct sequencing revealed a heterozygous missense mutation in codon 202 of exon 2 of KRT5 (c.605T>A), which led to an amino acid change (p.L202Q) in the patients with EBS but was absent from the unaffected family members and 100 population controls. In conclusion, a novel missense mutation in the KRT5 gene was identified that had a pathogenic role in EBS in the population studied, which enriches the germline mutation spectrum of the KRT5 gene.
| S-EPMC4665702 | biostudies-literature
Project description:The blistering skin disorder epidermolysis bullosa simplex (EBS) results from dominant mutations in keratin 5 (K5) or keratin 14 (K14) genes, encoding the intermediate filament (IF) network of basal epidermal keratinocytes. The mechanisms governing keratin network formation and collapse due to EBS mutations remain incompletely understood. Drosophila lacks cytoplasmic IFs, providing a 'null' environment to examine the formation of keratin networks and determine mechanisms by which mutant keratins cause pathology. Here, we report that ubiquitous co-expression of transgenes encoding wild-type human K14 and K5 resulted in the formation of extensive keratin networks in Drosophila epithelial and non-epithelial tissues, causing no overt phenotype. Similar to mammalian cells, treatment of transgenic fly tissues with phosphatase inhibitors caused keratin network collapse, validating Drosophila as a genetic model system to investigate keratin dynamics. Co-expression of K5 and a K14(R125C) mutant that causes the most severe form of EBS resulted in widespread formation of EBS-like cytoplasmic keratin aggregates in epithelial and non-epithelial fly tissues. Expression of K14(R125C)/K5 caused semi-lethality; adult survivors developed wing blisters and were flightless due to a lack of intercellular adhesion during wing heart development. This Drosophila model of EBS is valuable for the identification of pathways altered by mutant keratins and for the development of EBS therapies.
| S-EPMC4519992 | biostudies-literature
Project description:BackgroundEpidermolysis bullosa (EB) is a rare genetic disease with widely different clinical manifestations, but the relationship between genotype and phenotype is not fully understood. In the present study, we recruited a Chinese family in which two members had been diagnosed with localized EB simplex (EBS), with clinical manifestation, including blisters and erosions on the soles of the feet since infancy.ObjectiveTo identify and confirm the genetic variation in a Chinese family diagnosed as localized EBS.MethodsOur study included two patients, other healthy members of the family, and 100 normal controls. Genomic DNA samples were isolated from each participant, and then polymerase chain reaction (PCR) direct sequencing was performed.ResultsThe results of PCR direct sequencing revealed a novel heterozygous missense mutation in codon 461 of exon 7 of KRT5 (c.1382T>C), which led to an amino acid change (p.L461P) in the patients with EBS but was absent in unaffected family members and 100 unrelated control samples.ConclusionThe present study broadens the mutational spectrum of EBS, and this knowledge could be harnessed for prenatal screening, gene diagnosis, and gene therapy for localized EBS.
| S-EPMC7875216 | biostudies-literature
Project description:The goal of this study is to characterize the expression profile of Epidermolysis bullosa simplex-mottled pigmentation (EBS-MP) patient compared with normal subjects using genomic expression analyses. Microarray analyses were performed with RNA isolated from skin biopsies. Robust multiarray analysis (RMA) normalization and Smyth’s moderated t test were used to select differentially expressed genes. Expression profiling comparisons show that 52 genes are differentially expressed in EBS-MP patients compared to control subjects. Difference of expression for three genes (TYR, CCL22 , and ACVR1C ) was validated using real-time reverse transcription–polymerase chain reaction. Twelve genes were related to lipid biosynthesis process, two to keratinisation and skin pigmentation, Nineteen to cell growth and apoptosis, five to immune response and fourteen to predicted or less known function cluster. To our knowledge, the distinctive pattern of gene expression that characterizes EBS-MP versus healthy skin tissue has never been reported. RNA used for the microarrays analysis was isolated from superficial 2mm punch biopsies composed of mainly epidermis with minimal dermis amounts of normal-appearing skin of one EBS-MP patient and seven healthy volunteers.
2012-03-10 | E-GEOD-36406 | biostudies-arrayexpress